Conventionally, contamination and infection due to needle-stick injuries from injection needles, puncture needles and the like have been a problem in medical facilities. In particular, recently, as hepatitis B, hepatitis C, HIV (human immunodeficiency virus) and the like have become a widespread social issue, there is a demand for systems that actively prevent the occurrence of accidents such as needle-stick injuries and the like.
As a way to prevent needle-stick injuries, various injection needle devices that have a structure in which a cannula is covered by a cover when injection needles or puncture needles are collected after use have been proposed. In most cases, such systems for preventing needle-stick injuries that have been proposed so far have cylindrical protection covers (hereinafter, referred to as shields), and the shields can slide with respect to rigid needles. That is, the system is configured such that the rigid needle either can be exposed or covered by the shield according to the sliding state of the shield.
Patent Document 1 discloses one example of a conventional medical needle device. This medical needle device includes: a winged shield 212 in which a wing portion 273 is connected with a substantially cylindrical shield tube (see FIG. 16); a hub 210 that is inserted into the shield tube movably in an axial direction and has a connection end 264 connected with an infusion tube (see FIG. 17); and a rigid needle that is fixed to the hub 210 (not illustrated). In the case where the hub 210 is positioned in an inner bore of the winged shield 212, the rigid needle protrudes toward an outside of the shield tube 212. The protruding rigid needle is stored into the inner bore of the winged shield 212 by allowing the hub 210 to slide toward a rear end side of the winged shield 212.
As shown in FIG. 18, in this conventional medical needle device, a contact surface 259 of the hub 210 (see FIG. 17) is in contact with an end surface on a rear end side of the winged shield 212, thereby preventing the hub 210 from slipping out from a front end side of the winged shield 212. At the same time, a protruding portion 234 that is positioned in a groove 236 functions to prevent the hub 210 from sliding toward a rear side. After puncturing in this state, the rigid needle is drawn into the winged shield 212, and a shoulder portion 246 of the hub 210 (see FIG. 17) is in contact with an inner surface 287 of the winged shield 212 (see FIG. 16), whereby the hub 210 is held by the winged shield 212.
FIGS. 19 to 20B show another example of the conventional medical needle device. The medical needle device shown in FIGS. 19 to 20B is constituted by a rigid needle 100, a hub 200, a tube 300 and a shield tube 400 that stores the hub 200 therein such that it can hold the hub 200. The shield tube 400 is provided with a wing 500 on its front end side. The hub 200 can slide in an axial direction inside the shield tube 400. As shown in FIG. 19, when a predetermined length of the rigid needle 100 protrudes from a front end of the shield tube 400, if a hook 222 of an engagement arm 211 is engaged with an engagement hole 410 of the shield tube 400, the sliding of the hub 200 toward a rear end side of the shield tube 400 is inhibited. After the use, by pinching the engagement arm 211 with fingers, the engagement is released, and the hub 200 is allowed to slide toward the rear end side of the shield tube 400. As shown in FIGS. 20A and 20B, an annular convex portion 220 collides with a step portion 420, thereby inhibiting the movement of the hub 200 toward the rear end side of the shield tube 400. At the same time, a base end side surface 231 of the annular groove 230 and a front end of a flexible abutting member 430 collide with each other, thereby the movement of the hub 200 toward the front end side of the shield tube 400 also is prevented. At this time, a cutting edge 111 of the rigid needle 100 is stored in the shield tube 400 completely (see, for example, Patent Document 2).
Patent Document 1: JP 5(1993)-503019 A
Patent Document 2: JP 10(1998)-85333 A
However, in the case where the hub 210 is held with the winged shield 212 by the engagement utilizing concave and convex shapes or a step, as the medical needle device described in Patent Document 1, adjustment of the holding force is limited. Since the above-described injection needle device is operated while holding the shield during a puncturing operation, it is necessary that the hub can be held securely with the shield and is integrated with the shield. Whereas, during a drawing operation for drawing the rigid needle into the shield after being used, it is preferable that the hub can slide easily inside the shield and the force for holding the hub by the shield is weak.
As described above, it is preferable that the holding force for storing the injection needle by the shield is set appropriately at the respective times of the puncturing operation and the drawing operation. However, in the conventional injection needle device that is explained above with reference to FIGS. 16 to 18, the hub is held by utilizing the concave and convex shapes, the step or the like, so that the appropriate holding force is not obtained at the respective times of the puncturing operation and the drawing.
On the other hand, the medical needle device described in Patent Document 2 can adjust the holding force at the respective times of the puncturing operation and the drawing operation to be more appropriate than the medical needle device described in Patent Document 1. However, since the hub 200 is provided with the engagement arm 211, the length of the hub 200 is increased accordingly. The medical needle device is sometimes fixed to a skin of a patient with an adhesive tape after the rigid needle punctures the patient, and thus preferably is as bendable as possible. However, the bendability of the hub is not taken into consideration. In most cases, the hub is formed by using a rigid material so as to secure the holding function by the shield, and it is almost impossible to bend the hub. Thus, it is preferable that a size of the hub is as small as possible.
These problems have been explained above by exemplifying the winged injection needle device that is provided with the rigid needle, but are common to a medical needle device further including a soft needle that is fixed to the front end portion of the shield and has an inner bore in which the rigid needle can be inserted, and a medical needle device having no wing. The above-described medical needle device that is provided with the soft needle particularly has a problem of a length of the hub. Since a part of the hub protrudes from the rear side of the shield in the state of storing the rigid needle into the shield, if the hub is long, the total length of the medical needle device is significantly long. If indwelling the soft needle in this state, a rear portion of the medical needle device is annoying.
The present invention provides a medical needle device that can hold a hub by a shield reliably during a puncturing operation, can allow the hub to slide easily inside the shield during a drawing operation, and is provided with a compact hub.